The influence of sintering conditions on microstructure and mechanical properties of titanium dioxide scaffolds for the treatment of bone tissue defects

In this study the attempts to improve mechanical properties of highly-porous titanium dioxide scaffolds produced by polymer sponge replication method were investigated. Particularly the effect of two-step sintering at different temperatures on microstructure and mechanical properties (compression test) of the scaffolds were analysed. To this end microcomputed tomography and scanning electron microscopy were used as analytical methods. Our experiments showed that the most appropriate conditions of manufacturing were when the scaffolds were heat-treated at 1500 degrees C for 1 h followed by sintering at 1200 degrees C for 20 h. Such scaffolds exhibited the highest compressive strength which was correlated with the highest linear density and the lowest size of grains. Moreover, grain size distribution was narrower with predominating fraction of fine grains 10-20 mu m in size. Smaller grains and higher linear density suggested that in this case densification process prevailed over undesirable process of grain coarsening, which finally resulted in improved mechanical properties of the scaffolds.